Technique	THIOGLYCOLLATE ,(/,)/,(
Principle	Thioglycollate medium was originally described by Brewer in 1940 as a medium permitting growth of strictly anaerobic and microaerophilic as well as aerobic organisms. The incorporated reducing agent sodium thioglycollate maintains a low Eh potential in the depths of the medium in tubes. The medium contains methylene blue as an indicator of oxidized and reduced conditions and a small amount (0.05%) of agar to decrease convecttion currents and dissolved oxygen. The broth can be used until about one-third of the fluid in the column has become oxidized as shown by the greenish colour. Thioglycollate medium can be prepared with a number of different carbohydrates and used for fermentation studies. Resazurin, a less toxic Eh indicator than methylene blue, is pink when oxidized
Cautions	Indicators are added after incubation because they are reduced under anaerobic conditions and lose their characteristics.
Method	The tubes are inoculated deep into the medium, incubated for 72 hr and then tested for acid production with a few drops of 0.5% neutral red.
Results
Positive control
Negative control
Reagents
Reference	Brewer (1940)J. Bact. 39:10